A. Stancak et al., THE EFFECTS OF RESPIRATORY PATTERN ON THE 0.1-HZ COMPONENT OF R-R INTERVAL VARIABILITY IN MENTAL ARITHMETICS, Studia psychologica, 35(1), 1993, pp. 65-72
The 0.1 Hz component of R-R interval variability associated with a spo
ntaneous blood pressure rhythm is considered to be a sensitive indicat
or of mental load. The aim of this study was to show whether a decreas
e in amplitude of the 0.1 Hz component during mental arithmetic was se
condary to the changes in respiratory pattern or whether it reflected
a direct task-related effect on the cardiac rhythm. ECG and respiratio
n were recorded in five min periods of rest and mental arithmetics in
thirteen young males. The respiratory signals were tape recorded in bo
th periods. The subjects were then asked to reproduce by their breathi
ng the previously recorded respiratory signals which were presented in
the form of a moving horizontal bar on the oscilloscope screen. It wa
s assumed that if a decrease of the 0.1 Hz component in mental arithme
tics compared with rest was secondary to the changes in respiratory pa
ttern then a similar decrease would be observed in the periods of repr
oduction of the mental arithmetic pattern compared to reproduction of
the resting pattern. The subjects reproduced the resting respiratory p
attern and the mental arithmetic respiratory pattern faithfully. The s
pectral parameter of the 0.1 Hz component was lower in mental arithmet
ics than at rest but the same amplitude difference was found in the tw
o reproduction periods indicating that a decrease in amplitude of the
0.1 Hz component during mental arithmetics could be attributed to the
changes in respiration.